java处理internet连接丢失
我设计了一个应用程序，在发出http请求之前检查互联网连接，它工作得很好，但问题是，当有互联网连接时，我切换移动数据，或在搜索数据期间强制失去互联网连接，应用程序崩溃。 如果在获取数据时失去了互联网连接，有没有办法让应用程序报告没有互联网连接？我检查并尝试使用广播接收器，但在我们要声明意图过滤器的安卓清单中，我找不到这些 我还使用加载程序而不是异步任务来执行网络请求 换句话说
我只是需要一个方法来处理 响应验证
该应用程序会检查设备是否已连接到互联网，并做出相应的响应。请求的结果经过验证，以说明服务器响应不好或服务器响应不足，这可能是由于在获取数据期间丢失了internet连接
enter code here
//这是获取数据的代码
公共课狂热{
public static ArrayList<word> fesh (){
// Create an empty ArrayList that we can start adding earthquakes to
ArrayList<word> words = new ArrayList<>();
// Try to parse the SAMPLE_JSON_RESPONSE. If there's a problem with the way the JSON
// is formatted, a JSONException exception object will be thrown.
// Catch the exception so the app doesn't crash, and print the error message to the logs.
final String RESPONSE = feshjson();
try {
// TODO: Parse the response given by the SAMPLE_JSON_RESPONSE string and
// build up a list of Earthquake objects with the corresponding data.
JSONObject rootobject = new JSONObject(RESPONSE);
JSONArray rootarray = rootobject.getJSONArray("features");
for(int i = 0;i<rootarray.length();i++){
JSONObject current = rootarray.getJSONObject(i);
JSONObject properties = current.getJSONObject("properties");
double magnitude = properties.getDouble("mag");
String place = properties.getString("place");
long date = properties.getLong("time");
String url = properties.getString("url");
word earthquake = new word(magnitude,place,date,url);
words.add(earthquake);
}
} catch (JSONException e) {
// If an error is thrown when executing any of the above statements in the "try" block,
// catch the exception here, so the app doesn't crash. Print a log message
// with the message from the exception.
Log.e("QueryUtils", "Problem parsing the earthquake JSON results", e);
}
// Return the list of earthquakes
// getword(words);
return words;
}
public static String feshjson(){
HttpURLConnection connection = null;
InputStream stream = null;
BufferedReader reader = null;
try {
URL url = new URL("https://earthquake.usgs.gov/fdsnws/event/1/query?format=geojson&starttime=2012-01-01&endtime=2012-12-01&minmagnitude=6");
connection = (HttpURLConnection) url.openConnection();
connection.connect();
stream = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(stream));
String line = "";
StringBuffer buffer = new StringBuffer();
while ((line = reader.readLine()) != null) {
buffer.append(line);
}
return buffer.toString();
} catch (MalformedURLException e) {
e.printStackTrace();
new MainActivity().Nonetwork();
}
catch (ConnectException ex)
{
ex.printStackTrace();
new MainActivity().Nonetwork();
}
catch (SocketException ex)
{
ex.printStackTrace();
new MainActivity().Nonetwork();
}
catch (SocketTimeoutException ex)
{
ex.printStackTrace();
new MainActivity().Nonetwork();
}
catch(NullPointerException ex)
{
ex.printStackTrace();
new MainActivity().Nonetwork();
}
catch (Exception e)
{
e.printStackTrace();
new MainActivity().Nonetwork();
}
finally {
if (connection != null) {
connection.disconnect();
}
try {
if (stream != null) {
stream.close();
}
} catch (IOException e) {
e.printStackTrace();
new MainActivity().Nonetwork();
}
}
return null;
}
}
//this is the method to display no network
public void Nonetwork(){
TextView text = (TextView) findViewById(R.id.texto);
text.setText("no internet");
text.setVisibility(View.VISIBLE);
}``
//this is what my Log looks like
05-25 23:50:46.029 22283-22308/? E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
Process: com.example.安卓.myquake, PID: 22283
java.lang.RuntimeException: An error occured while executing doInBackground()
at 安卓.os.AsyncTask$3.done(AsyncTask.java:300)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
at 安卓.os.Handler.<init>(Handler.java:200)
at 安卓.os.Handler.<init>(Handler.java:114)
at 安卓.app.Activity.<init>(Activity.java:793)
at 安卓.support.v4.app.BaseFragmentActivityGingerbread.<init>(BaseFragmentActivityGingerbread.java:34)
at 安卓.support.v4.app.BaseFragmentActivityHoneycomb.<init>(BaseFragmentActivityHoneycomb.java:29)
at 安卓.support.v4.app.BaseFragmentActivityJB.<init>(BaseFragmentActivityJB.java:29)
at 安卓.support.v4.app.FragmentActivity.<init>(FragmentActivity.java:77)
at 安卓.support.v7.app.AppCompatActivity.<init>(AppCompatActivity.java:64)
at com.example.安卓.myquake.MainActivity.<init>(MainActivity.java:0)
at com.example.安卓.myquake.Fesh.feshjson(Fesh.java:129)
at com.example.安卓.myquake.Fesh.fesh(Fesh.java:39)
at com.example.安卓.myquake.Arrayloader.loadInBackground(Arrayloader.java:28)
at com.example.安卓.myquake.Arrayloader.loadInBackground(Arrayloader.java:18)
at 安卓.content.AsyncTaskLoader.onLoadInBackground(AsyncTaskLoader.java:312)
at 安卓.content.AsyncTaskLoader$LoadTask.doInBackground(AsyncTaskLoader.java:69)
at 安卓.content.AsyncTaskLoader$LoadTask.doInBackground(AsyncTaskLoader.java:57)
at 安卓.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
共 (0) 个答案